This article sums up what you need to know about the new NFPA 68 standard on explosion venting for combustible dusts. The information here can help you better understand what's changed in this revised standard and how it will affect your dust collection choices today and in the future.

1. EXPLOSION VENTING
REQUIREMENTS
F O R D U S T C O L L E C T O R S
5 W A Y S N E W
AFFECT YOU

2. 1. NFPA 68 has changed from a
“guideline” to a “standard.”
NFPA 68 now includes mandatory
requirements for dust collection
applications with combustible
dusts. This change from a
“guideline” to a “standard,” which
incorporates much more stringent
requirements than past editions,
is echoed by OSHA’s recent launch
of its National Emphasis Program
(NEP) on safely handling combustible
dusts. Simply stated, it’s NFPA’s role
to set the standard and the role of OSHA
and local authorities to enforce it.

3. 2. You need to determine
whether your dust is explosive.
NFPA classifies dusts according to their
explosibility -- that is, their KSt values. Class
1 dusts are rated below 200 KSt, Class
2 dusts range from 200 to 300 KSt, and
Class 3 dusts are rated above 300 KSt. As
a rule of thumb, when dusts approach 600
KSt, they’re so explosive that wet collection
methods are recommended.

4. 3. You need to commission a
hazard analysis of your dust
collection system.
Chapter 4 in NFPA 68 introduces a new hazard
analysis requirement that states “the design
basis deflagration hazard scenario shall be
identified and documented” (4.2.3.1) and “a
documented risk evaluation acceptable to
the AHJ shall be permitted to be conducted
to determine the level of protection to be
provided” (4.2.3.2).
This means that you’ll have to
commission a hazard analysis (also called risk
evaluation) of your plant’s dust collection system
and keep the report on file to show to the local fire
marshal or other AHJ at a moment’s notice.

5. 4. You need to maintain
extensive documentation.
A hazard analysis isn’t the only documentation
required by NPFA 68. In Chapter 11, the
standard lists 19 documents that you
must now maintain on file to satisfy the
local fire marshal or other AHJ. Some of
these - such as suppliers’ equipment data
sheets and drawings, instruction manuals,
and specifications - are readily obtained.
Obtaining others - including a combustible
material (dust) properties test report,
user documentation of conformity with
applicable standards, and employee training
requirements - will present a more substantial
challenge to you or the plant or safety
engineer in charge

6. 5. You need to schedule an
annual inspection of your dust
collection system’s explosion
venting equipment.
Chapter 11 also stipulates that your explosion
venting equipment must be inspected at least
annually and possibly more often, based on
your documented operating experience. This
inspection’s objective is simply to determine that
all of the system’s components are operating
correctly. The chapter outlines a 16-point vent
inspection with this objective in mind (11.4.4). Your
plant owner or operator must also verify in writing
that your process material hasn’t changed since the last
inspection (11.4.5). You must file the inspection reports
with your other required documentation (11.2).

7. READ THE ENTIRE ARTICLE!
https://www.camfilapc.com/industry_articles/five-ways-new-explosion-
venting-requirements-for-dust-collectors-affect-you